Hepper is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Top 16 Fish for 2 & 2.5-Gallon Tanks (with Pictures)

Lindsey Stanton Profile Picture

By Lindsey Stanton

mix colors of platy fishes in a tank

Fishkeeping is an enjoyable venture for people who have a passion. Interestingly, most people don’t know that fish have feelings. When they have stress issues, they tend to hide and become uncomfortable. They become aggressive toward one another and fight. One of the key factors in stressing the fish is space—and that’s why keeping fish in limited space requires some good planning.

The 2 and 2.5-gallon tanks are also called Nano tanks. People who love fishing sometimes get confused, wondering whether it is safe to keep fish in such tanks. Nano tanks are small but can hold several fish comfortably. The beauty of Nano tanks is that they are versatile—they need little effort in the setup process, and managing is effortless. Moreover, they are cheap and can be kept in small spaces.

So, if you have a small space in the office, apartment, or garden, you can keep your fish. If you are a beginner and want to venture into fishing, this is an excellent starting point. Are you wondering what the best fish to keep in a Nano tank are? Continue reading…

fish divider

The 16 Top Fish for 2 and 2.5-Gallon Tanks

1. Small Barb Fish

tiger barbs
Image Credit: Andrej Jakubik, Shutterstock

Small barb fish are tiny at around 2 inches. In addition, they are easy to take care of, requiring a tank temperature of 75–80°F.  But we have different types of barbs. The ones suitable for 2 to 2.5-gallon tanks are cherry and checkerboard barbs.

The correct number of fish to keep in these tanks is five. This is because they are aggressive and keep fighting. Since they are shoaling fish, they have a hierarchy. That makes them compete for space so that they can prove their strengths and abilities.

2. Beta Fish

red and blue betta in aquarium
Image Credit: Arunee Rodloy, Shutterstock

Keeping a beta fish is very easy since they are small at 2.1 inches. They can survive in minimal places, and most people keep them even in bowls. The tank temperature should be 80°F with a pH level of 7.0. They are beautiful and bred in many colors.

It is wise to clean the tank regularly to remove any toxins. But these are immaculate fish, so the frequency of changing the water is minimal. Also, you can keep as many females as your tank can hold but never keep two males in one tank. That is because they can be aggressive and kill one another.

3. Small Tetras

congo tetra fish in aquarium
Image Credit: Grigorev Mikhail, Shutterstock

Small tetras are 2 inches and require a tank temperature of 77–82°F and a pH level of 5–7, and you can keep 2 to 3 in one tank. We have different types of tetras, and the ones suitable for this size of tank are cardinal tetra, lemon tetra, neon tetra, and black tetra.

They are peaceful and serene; thus, they don’t require special maintenance treatment. You can add some plants to the tank because they like to hide.

4. Cory Catfish

Corydoras Catfish
Image Credit: Rethinktwice, Pixabay

They are easy to maintain and require a 60–70°F tank temperature with a pH level of 5 to 5.7. Cory catfish are beautiful, and even in adulthood, they grow up to 2.5 inches. However, they don’t like staying alone since they get very lonely and can even die.

You are required to keep them in a group of three to avoid loneliness. Cory catfish are a blend of personality and utility. That’s why they thrive in such a small tank.

5. Black Molly

black molly
Image Credit: Kocsis Sandor, Shutterstock

Black molly fish are versatile and thrive in fresh or salty water. They require a 68–82°F tank temperature with a pH level of 7.0–7.8. Their body size is between 2–3 inches and requires well-planned care since they make their tank dirty regularly.

You can keep a male and female since they produce and give birth. But you are not limited to that since there are different types, and you can opt to mix. For example, black molly is known to eat their babies, so you might consider whether to keep them or not.

6. Danois

danio zebrafish
Image Credit: topimages, Shutterstock

They are suitable for beginners since they are effortless to keep. They reach up to 2 inches, which means they are a good choice for a 2 to 2.5-gallon tank. However, they require a tank temperature of 70–78°F with a pH of 7 to 7.8. The good thing about Danois is that you can still adjust the temperature, and they will survive.

You can feed them almost anything since they are active and are not picky about their diet. In addition, Danois fish are easily recognizable from other fish because of their bright horizontal stripes. Finally, they thrive well when kept in a group.

7. Bloodfin Tetras

bloodfin tetra in aquarium
Image Credit: Karel Zahradka, Shutterstock

They have a body size of 2–2.5 and are very beautiful. Bloodfin tetras thrive well in a 70 –80°F tank temperature with a pH level of 6–8. You can keep up to five since they hate living alone.  If you take care of blood fin tetras, they can live up to 10 years.

Bloodfin tetras are not so keen on water science. Their silver body which is noticeable from a distance can survive in frigid water. They love eating flakes and freeze-dried foods. Their close relatives are ember and neon tetras.

8. White Cloud Mountain Minnow

white cloud mountain minnows
Image Credit: Grigorev Mikhail, Shutterstock

These Fish are easy to keep, and their size ranges from 1 to 1.5 inches. They do well in tank temperatures of 60–72°F and pH levels of 6.0–8.0. They have similarities with tetras, so you can decide to keep them together.

The white cloud can do well in many temperatures and water conditions. They have vibrant colors and are gorgeous.

Keeping them in a group is a fantastic idea since they tend to lose color when left alone. If you take good care of white clouds, they can live up to 5 years.

9. Kuhli Loach

Kuhli Loach in aquarium
Image Credit: Roberto Dani, Shutterstock

Kuhli loach fish are a bit hard to keep. They thrive in a 75–86°F tank temperature with a pH level of 5.5–7.0. Their body size ranges from 2–4 inches.

They don’t like getting out in the daytime. They normally stay at the bottom, and you will find them mostly at night.

That’s why it is good to have tunnels or caves in your tank to give them some hiding ideas. Their diet should be strictly observed since they require a different diet compared to others. If well taken off, Kuhli loach can live for a long time.

10. Wild–Type Guppies

two Wild Yellow guppies on Black Background
Image Credit: Nantawat Chotsuwan, Shutterstock

These are difficult fish to keep. They require a lot of care. On the other hand, wild-type guppies do well in a tank temperature of 78–82°F with a pH level of 6.8–7.6.

They grow up to 15 inches and are exotic compared to other guppies. But most fish keepers love to keep guppies. They can become sick often and require antibacterial medication. Wild-type guppies don’t like to live alone, so consider keeping them in groups.

Since they are tiny, you can have a number of them in your 2–2.5 gallon tank. You can feed them with algae and aufwuchs.

11. Swordtails

red swordtail
Image Credit: Arunee Rodloy, Shutterstock

Swordtails have different unique colors. You can find them in red and green. They require moderate care and can do well in a tank temperature of 65–82°F. The pH Level should be 7– 8.4, and they can grow up to 6.3 inches.

They live well in groups since they are tough. In most cases, they are known to do well in different conditions, and fitting in a small space is not an issue. Consider feeding them with proteins like worms, shrimps, and algae.

12. Blind Cave Tetras

group of Blind Cave Fish or Mexican Tetras
Image Credit: Tatiana Belova, Shutterstock

They require moderate care with a 68–77°F tank temperature with a pH level of 6.5–8.0. They are not very small since they grow up to 7 inches. The beauty of blind caves is that they don’t require any lighting or heating.

Their name is blind caves, so they are blind. When setting up their tank, ensure you add caves for them to hide.  A screen to watch their movement is also necessary. When they are stressed, they jump high, and they love living in groups.

13. Salt and Pepper Corydoras

Salt and Pepper Corydora at the bottom of the tank
Image Credit: Pavaphon Supanantananont, Shutterstock

Taking care of salt and pepper corydoras is very hard.  Salt and pepper Corydoras require a 72–79°F tank temperature with a pH level of 6.2–7.2. They are among the tiniest fish that are suitable for 2–2.5-gallon tanks. They grow up to 0.75 inches.

These fish are quiet and vivid. Their body has a light tan with dark sliver spotting. Additionally, they know how to clean themselves and take care of their surroundings.

It’s advisable to keep them in groups and add some plants to the tank.

14. Small Live Bearers

red scarlet guppy
Image Credit: Pavaphon Supanantananont, Shutterstock

Keeping Small Live Bearers is a challenge. They require a 74–78 82.4°F tank temperature with a pH level of 7.0–8.4. In addition, they are tiny in size averaging between ½–¾ inches. But they are cute and have a variety of colors.

Their breeding cycle is relatively high, so you can’t keep many in your tank. Small Live Bearers make a mess within a short time. That’s why it is hard to keep them since they require a lot of care.

15. Platies

Red Wagtail Platy
Image Credit: Joan Carles Juarez, Shutterstock

Platies thrive well in a 70–80°F tank temperature and a pH level of–6.0–8.0.  Their average size is between 2.5–3 inches. What makes them distinctive from other fishes are their thick body, sharp nose, and huge eyes.

Most kids love them because they are cute and have different colors of red, blue, orange, and yellow colors.

Platies are suitable for beginners since they require minimal maintenance. They do well in communities so you can mix up with other fish.

16. Black Skirt Tetra

black skirt tetra
Image Credit: Joan Carles Juarez, Shutterstock

They are beautiful kinds of fish that do well in a tank temperature of 70–85°F. They grow up to 2 inches and require a pH level of 6.8–7. When you look closely, you will notice two vertical stripes located at the front of the body. The anal and dorsal are dark and very distinct.

The color, though, changes as they grow. Black skirt tetras can live as long as five years if well taken care of. That is why it is advisable to change their water regularly since they don’t like dirty water. Consider keeping at least two in your tank since they get lonely.

wave tropical divider


When setting up a 2 to 2.5-gallon tank for your fish, it is good to consider lighting, proper hygiene, temperature, filtration, etc. However, most of these fishes require minimal care; thus, they can do so well.

The ones that are challenging to keep still do well if you put in some extra effort. You can adapt a routine to take care of them, so consider including them in your tank to enjoy the beauty of fish keeping.

Featured Image Credit: Thanes Pruttivanichakul, Shutterstock

Related Articles

Further Reading

Vet Articles

Latest Vet Answers

The latest veterinarians' answers to questions from our database